1. Field of the Invention
The field of the invention is that of systems for the exchange of data between two elements capable of being coupled together.
More specifically, the system of the invention finds application in the exchange of data between at least one movable, insertable electronic object and at least one transfer device wherein:
said specific transfer device comprises means for the transfer of data into and/or out of the memory of the insertable object;
said insertable object, hereinafter called a "smart insertable object" comprises an electronic memory associated with an access circuit and coupling means accessible from the exterior of the insertable object enabling the temporary coupling, by any means, of said insertable object with said transfer object.
In the sense used in relation to the present invention, the coupling of the insertable object with the transfer device can be done not only by the total or partial physical introduction of the insertable object into the transfer device but also by the simple placing of one against the other or, again, by any other type of physical arrangement enabling the exchange of data between them.
For example, the system according to the invention can be applied to the exchange of data between a microcomputer and an electronic element that can be inserted into the disk drive of the microcomputer, or into a memory card reader.
2. Description of the Prior Art
This situation corresponds notably to the teachings of the prior patent documents EP-A-0 373 411, U.S. Pat. No. 4,701,601 and U.S. Pat. No. 4,791,283.
The patent document EP-A-0 373 411 published on Jun. 20, 1990 relates to an artefact of an element of a magnetic strip card, diskette or cassette type capable of being inserted in a data-processing machine such as a computer or a microcomputer. According to this document, the insertable element is fitted out with a processor, a data and/or program memory, and an interface emulating the means of communication used by a standard insertable element to communicate with the data processing equipment. The processor makes it possible to carry out operations of coding and/or decoding and encrypting and/or decrypting message signatures or access controls which are, for example, the conditions for the use of a microcomputer. One of the vital elements of this type of system is the electrical supply of the interface of the insertable element. According to this document, the power source may be constituted by a cell or, again, by a generator activated by the movement of insertion of the insertable element into the data processing equipment.
The document U.S. Pat. No. 4,701,601 delivered on Oct. 20, 1987 describes the general principle of a microprocessor-based portable bank transaction card comprising data processing peans and means to emulate a magnetic strip so that it can be compatible with bank terminals for the reading of magnetic strip cards. This patent mentions the problems of the availability of a source of power sufficient to supply the card, notably means for the emulation of a magnetic strip (col. 5, 1.64-67) and proposes the use of solar panels for recharging an accumulator in minimizing the emulation periods (col. 7, 11.31 to 54).
The U.S. Pat. No. 4,791,283 delivered on Dec. 13, 1988 also relates to a microprocessor-based portable bank card comprising data processing means and means to emulate a magnetic strip. More specifically, it describes a possible configuration and geometry of circuits to make means to generate a magnetic field throughout practically the entire length of a card, enabling the emulation of each binary element (bit) of information to be transmitted. The electrical supply to the circuits is done by an external energy source (col. 4, II.29-35).
These two prior art documents relate specifically to the field of bank cards. They disclose no means of configuration of the data exchanged between the card and the transaction terminal, and do not satisfactorily resolve the problem of supplying the microprocessor card with electrical power.
These problems are, however, decisive ones.
Generally speaking, a portable or insertable object such as a "smart" diskette or memory card, namely provided with at least one electronic memory associated with access circuits is characterized, firstly, by its independence and, secondly, by its processing capacity.
As regards the processing of the exchanged data, one of the problems that arises relates to the compatibility of the data bit rates among the processing means of the transfer device, the coupling means and the circuits providing access to the electronic memory of the insertable object. More specifically, notably in the case of magnetic coupling means such as those used by the exchange of data between a diskette and the disk drive of a microcomputer, the bit rate is standardized, typically at a value of 250 to 500 Kbits per second.
The reception or transmission of data elements at these bit rates calls for a corresponding processing capacity on the part of the circuits providing access to the electronic memory of the insertable object. The term "circuits providing access to the memory" here as well as further below implies any means capable of managing access to said memory, including a microprocessor or a microcontroller (a microprocessor incorporating interface elements such as an UART or universal asynchronous receiver transmitter (asynchronous serializer/deserializer) and/or memory of its own).
Now, in the current state of art, it is difficult to meet this requirement under commercially and technically acceptable conditions.
It is true that there are compact processors capable of being mounted in a flat element such as a memory card or diskette, and capable of managing data elements at these flow rates. However, these processors consume a quantity of power that exceeds the capacity of the best performing cells now available at reasonable cost (for example Li--Mg cells), for a satisfactory period of use in the desired application.
Furthermore, there do exist microprocessors which are more economical in terms of power consumed, but their performance characteristics are not sufficient to process the data bit rates considered.
Finally, we may envisage a specific microprocessor configuration adapted to these constraints, but the cost of designing such components and the relatively small size of the market envisaged for these specific microprocessors makes this approach unprofitable in principle.
Furthermore, the magnetic coupling means used in the disk drives of microcomputers generally include specific data coding means with which they have to be compatible. Thus, the microcomputers of the type marketed by IBM used a coding called MFM (modified frequency modulation), and those marketed by the Apple firm used a coding called GCR (group coded recording). The MFM, GCR or equivalent codings are essentially aimed at coding information elements in a form adapted to the constraints of magnetic transmission, and any system of data exchange in this context should take account of these constraints.